git: --getctime will now follow renames back to the original creation of a file.

This will be a bit more expensive, but --getctime does not need to be fast.
And getting the real creation time a very useful when untangling blog
histories that involve renames.

1 files changed, 5 insertions, 3 deletions

diff --git a/IkiWiki/Plugin/git.pm b/IkiWiki/Plugin/git.pm
index ad58231e0..e10283f59 100644
--- a/IkiWiki/Plugin/git.pm
+++ b/IkiWiki/Plugin/git.pm
@@ -613,9 +613,11 @@ sub rcs_getctime ($) {
 	# Remove srcdir prefix
 	$file =~ s/^\Q$config{srcdir}\E\/?//;
 
-	my @sha1s = run_or_non('git', 'rev-list', 'HEAD', '--', $file);
-	my $ci    = git_commit_info($sha1s[$#sha1s], 1);
-	my $ctime = $ci->{'author_epoch'};
+	my @raw_lines = run_or_die('git', 'log', '--reverse', '--follow',
+		'--pretty=raw', '--raw', '--abbrev=40', '--always', '-c',
+		'-r', '--', $file);
+	my $first = parse_diff_tree("", \@raw_lines);
+	my $ctime = $first->{'author_epoch'};
 	debug("ctime for '$file': ". localtime($ctime));
 
 	return $ctime;